This invention relates to a method of assigning coded quantities to provide an identification of particular aspects of a physical system. The codes preferably provide information with regard to at least two characteristics of the physical system, and are assigned in such a way that any misreading is likely to have minimal effect.
The present invention is specifically directed to a method of providing a coded identifier through a voltage associated with particular types of fuel injectors. The identifier provides feedback to a control for driving the fuel injectors on characteristics of the fuel injectors. The fuel injectors can vary with manufacturing tolerances, and by sensing the identifying voltage the control can identify how the particular fuel injector would be best controlled.
A series of distinct voltages are associated with different combinations of two characteristics. The control reads an electronic signal influenced by the voltage, and can thus identify the particular code, and thus the combination of characteristics. This basic system is disclosed in co-pending patent application Ser. No. 09/536,365, filed on Mar. 27, 2000.
One challenge with this type of system would be identification errors, in which the control misidentified the particular signal as being a code other than the proper code. It would be desirable to minimize the detrimental effect of when a particular monitored voltage is associated with particular set of characteristics by the control, but wherein the injector actually possesses a different set of characteristics than that which the control has identified. A number of different factors can influence and cause such errors. As examples, the disclosed embodiment utilizes resistors to provide the code voltage. As with any manufactured item, there are tolerances within the resistors. Thus, the resistors themselves can result in voltage errors. Moreover, the voltage sources which drive the system may also vary from a predicted value, and can also result in error.
The present invention minimizes the ill effect of any such reading error by assigning the coded information in a fashion other than beginning at the same point within a row or column and returning to this beginning point. This will be explained below. If the codes are assigned in rows and columns, then it will be true that adjacent code numbers can be associated with physical states of the system wherein both characteristics are different, and the characteristics may be different by several factors.
Any misreading error is likely to be between adjacent code values. The present invention minimizes the detrimental effect of any misreading error by assigning adjacent code values in such a way that between adjacent values, only one characteristic changes, and that characteristic only changes by a one value.
In the disclosed embodiment of this invention, characteristics are associated with a particular system in at least two sets of different values. The combination of the two characteristics are assigned a code value associated with a physical quantity, such that each next increasing code value is assigned to a combination of the two characteristics that only changes one of the characteristics. Moreover, the characteristic that changes only changes by one value between any two adjacent code values.
The invention is disclosed for associating voltages and codes for two characteristics of a fuel injector, however, the method for identifying code values and storing data can be utilized for many other physical systems. Most preferably, the code is identified by an identifying resistor. Further, most preferably the voltage value differences between adjacent codes increase as the absolute value of the voltage increases. This aspect is explained in greater detail in the co-pending patent application entitled xe2x80x9cUtilizing Increasing Width for Identification Voltages,xe2x80x9d Ser. No. 09/686,253 filed Oct. 11, 2000.
In a disclosed embodiment of this invention, the code values are assigned such that if they were arranged in an array, they would extend in a spiral fashion. In other embodiments, the values extend in a back and force fashion, in a serpentine fashion, or in a xe2x80x9cnecklacexe2x80x9d or xe2x80x9cdouble-uxe2x80x9d arrangement. While the majority of embodiments are two dimensional, one embodiment does extend the invention to a three dimensional array, wherein there are three characteristics being identified. Moreover, while all of the specifically listed embodiments are xe2x80x9csquarexe2x80x9d, non-square arrays also benefit from this invention.
These and other features of the present invention can be best understood from the following specification and drawings, following which is a brief description.